Ringing in the ears (tinnitus) is noise originating in the ear rather than in the environment. It is a symptom and not a specific disease. Tinnitus is very common—10 to 15% of people experience it to some degree.

The noise heard by people with tinnitus may be a buzzing, ringing, roaring, whistling, or hissing sound and is often associated with hearing loss. Some people hear more complex sounds that may be different at different times. These sounds are more noticeable in a quiet environment and when people are not concentrating on something else. Thus, tinnitus tends to be most disturbing to people when they are trying to sleep. However, the experience of tinnitus is highly individual. Some people are very disturbed by their symptoms, whereas others find them quite bearable.

Subjective tinnitus is by far the most common type. It is caused by abnormal activity in the part of the brain responsible for processing sound (auditory cortex). Doctors do not fully understand how this abnormal activity develops.

Objective tinnitus is much less common. It represents actual noise created by structures near the ear. Other people can sometimes hear the sounds of objective tinnitus if they listen closely.

Causes

Subjective tinnitus

More than 75% of ear-related disorders include tinnitus as a symptom and people who have hearing loss, regardless of cause, often develop tinnitus . The most common causes include

Other causes of tinnitus include middle ear infections, disorders that block the ear canal (such as an external ear infection [external otitis], excessive ear wax, or foreign bodies), problems with the eustachian tube (which connects the middle ear and the back of the nose) due to allergies or other causes of obstruction, otosclerosis (a disorder of excess bone growth in the middle ear), and temporomandibular disorders. An uncommon but serious cause is an acoustic neuroma, a noncancerous (benign) tumor of part of the nerve leading from the inner ear.

Objective tinnitus

Objective tinnitus usually involves noise from blood vessels near the ear. In such cases, the sound comes with each beat of the pulse (pulsatile). Causes include

Turbulent flow through the carotid artery or jugular vein

Certain middle ear tumors that are rich in blood vessels

Malformed blood vessels of the membrane covering the brain

The most common noise is the sound of rapid or turbulent blood flow in major vessels of the neck. This abnormal blood flow may occur because of a reduced red blood cell count (anemia) or a blockage of the arteries (atherosclerosis) and may be worsened in people with poorly controlled high blood pressure (hypertension). Some small tumors of the middle ear called glomus tumors are rich in blood vessels. Although the tumors are small, they are very near the sound-receiving structures of the ear, and blood flow through them can sometimes be heard (only in one ear). Sometimes, blood vessel malformations that involve abnormal connections between arteries and veins (arteriovenous malformations) develop in the membrane covering the brain (the dura). If these malformations are near the ear, the person sometimes can hear blood flowing through them.

Less commonly, spasms of muscles of the palate or the small muscles of the middle ear cause clicking sounds. These sounds do not follow the beat of the pulse. Such spasms often have no known cause but may be due to tumors, head injury, or diseases that affect the covering of nerves (for example, multiple sclerosis).

Evaluation

Not all tinnitus requires evaluation by a doctor. The following information can help people decide whether a doctor's evaluation is needed and help them know what to expect during the evaluation.

Warning signs

Certain symptoms and characteristics are cause for concern. They include

Tinnitus in only one ear

Any neurologic symptoms (other than hearing loss), particularly difficulty with balance or walking, but also vertigo or difficulty seeing, speaking, swallowing, and/or talking

When to see a doctor

People with warning signs should see a doctor right away. People without warning signs in whom tinnitus recently developed should call their doctor, as should people with pulsatile tinnitus. Most people with tinnitus and no warning signs have had tinnitus for a long time. They can discuss the matter with their doctor and be seen at a mutually convenient time.

What the doctor does

In people with tinnitus, doctors first ask questions about the person's symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination may suggest a cause of the tinnitus and the tests that may need to be done (see Table: Some Causes and Features of Tinnitus).

During the medical history, doctors ask about the following:

The nature of the tinnitus, including whether it is in one or both ears and whether it is constant or pulsatile

Whether the person has any neurologic symptoms

Whether the person has been exposed to loud noise or to drugs that can affect the ears

During the physical examination, doctors focus on examining the ears (including hearing) and the neurologic system. They also listen with a stethoscope over and near the person's ear and on the neck for sounds of objective tinnitus. The findings often suggest a cause.

Some Causes and Features of Tinnitus

Cause

Common Features*

Tests

Subjective tinnitus (typically a constant tone and accompanied by some degree of hearing loss)

Testing

Most people should have a formal hearing test done by either the doctor or a hearing specialist (audiologist). People with tinnitus in only one ear and hearing loss should have gadolinium-enhanced magnetic resonance imaging (MRI). People with tinnitus in only one ear and normal hearing should have an MRI if tinnitus lasts more than 6 months. People with pulsatile tinnitus often require magnetic resonance angiography (MRA) and sometimes angiography.

Treatment

Attempts to identify and treat the disorder causing tinnitus are often unsuccessful. However, correcting any hearing loss (for example, with a hearing aid) relieves tinnitus in about half of people.

Treatment of stress and other mental conditions (such as depression) may help. Many people are reassured if it is learned that their tinnitus is not caused by a serious disorder. Caffeine and other stimulants can worsen tinnitus, so people should try to avoid these.

Various techniques can help make tinnitus tolerable, although the ability to tolerate it varies from person to person. Many people find that background sound helps mask the tinnitus and helps them fall asleep. Some people play background music. Other people use a tinnitus masker, which is a device worn like a hearing aid that produces a constant level of neutral sounds. For the profoundly deaf, an implant in the cochlea (the organ of hearing) may reduce tinnitus but is only done for people with severe to profound hearing loss in both ears. If these standard techniques are not helpful, people may want to seek treatment in clinics that specialize in the treatment of tinnitus.

Key Points

Most tinnitus is due to causes that are not dangerous, for example, exposure to loud noise, aging, Meniere disease, and use of certain drugs.

In many cases, the cause is unknown.

Findings that are of concern include tinnitus accompanied by any neurologic symptoms and tinnitus in only one ear (particularly when accompanied by hearing loss, dizziness, and/or balance difficulty).

Tinnitus rarely can be stopped, but certain techniques help people manage their symptoms effectively.

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